In a study of the effects of text familiarity, task type, and language proficiency on university students’ Language for Specific Purposes Ability (LSPA) test and task performances, 541 senior and junior university students majoring in electronics took the Task-Based Reading Test (TBRT). Variance analyses indicated that text familiarity, task type, and language proficiency, as well as the interaction between any given pair of these and also among all of them resulted in significant differences in participants’ overall and differential test and task performances. In addition, regression analyses revealed that the greatest influence on subjects’ overall and differential test and task performances was due to language proficiency. Text familiarity had the smallest effect on students' test and task scores. Compared to text familiarity, task type was a stronger predictor of variance in test and task performance.